Moves ownership of the cc::Display's BeginFrameSource out of Display.

cc/test/test_compositor_frame_sink.h

Index: cc/test/test_compositor_frame_sink.h
diff --git a/cc/test/test_compositor_frame_sink.h b/cc/test/test_compositor_frame_sink.h
index d35efed7355906472b3832a34a2cd124da1f265d..52b4aeca1125b315eaef00aa2674cb62b45a09aa 100644
--- a/cc/test/test_compositor_frame_sink.h
+++ b/cc/test/test_compositor_frame_sink.h
@@ -105,7 +105,9 @@ class TestCompositorFrameSink : public CompositorFrameSink,
   // Uses surface_manager_.
   std::unique_ptr<SurfaceFactory> surface_factory_;
 
-  // Uses surface_manager_.
+  std::unique_ptr<SyntheticBeginFrameSource> begin_frame_source_;
+
+  // Uses surface_manager_ and begin_frame_source_.
   std::unique_ptr<Display> display_;
 
   bool bound_ = false;